I've encountered an issue when an underlying table in SQL is changed, but the update isn't reflected after refreshing the extract in tableau.

the exact order:

Connect Tableau to a table in MS SQL

Extract data

Run an update statement in SQL on the sane table ( UPDATE TABLE SET FIELD = 'YES' WHERE YEAR = 2016)

Refresh extract

Tableau still displays data with old values, not updated to "YES"

I haven't confirmed this entirely - but I think this is sometimes solved by using a custom SQL "SELECT * FROM TABLE" instead of directly connecting to the table. If anyone has any insight, I would greatly appreciate the help.

Are you incrementally refreshing the extract? If so, no previous rows will be updated--it's a new records / append-only operation. If you're fully refreshing the data, I'd double check your extract filters, your datasource filters, and possibly any filters you have on your worksheet.

This is a full refresh, not incremental. Additionally there are no data source filters.

To clarify this point - Tableau is displaying information that outright no longer exists in the underlying SQL table. In other words, there are no more records that say "NO", they have all been updated to "YES". In this way, filters shouldn't be the source of the issue, as no records at all say "NO" regardless of filtering.